Research

Research goal: Enhance manufacturing competitiveness through digital innovation and intelligence.

Dr. Khoda leads the Digital Manufacturing (DM) research group in the Mechanical Engineering Department at The University of Maine (UMaine). The research focuses on novel design and manufacturing methodology for multi-functionality. I recently developed an additive manufacturing process with rods, which can address many of the current challenges faced by metal AM. The research marked a shift in the way scientists think about part-performance, allowing a synchronized approach between topology, data, material, and manufacturing/delivery systems. My research aims to increase the advanced manufacturing penetration in healthcare, aerospace, automotive, and consumer goods. My scholarly program objectives are to pursue the scientific questions in manufacturing science, procure major grant funding, to continue collaboration on projects through multidisciplinary teams.

Novel Metal Additive Fabrication with Thin Rod: Khoda, B. et. al. 2021 3DPAM; Khoda, B. et. al. 2021 Sci. Report; Khoda, B. et. al. 2021 3DPAM

Current 3D printing processes utilize low dimensional forms of feed-stock materials, i.e., powder, liquid vet, or semi-molten filament to construct metal parts. Their incremental consolidation often results in uncontrollable thermo-mechanical behavior in the tool-less 3DP process brings (a) diverse and amorphous (metastable) microstructure (b) higher contamination and (c) shrinkage and disconnected nodes. A novel additive metal structure process is developed with a continuous rod. Fabricating lattice structures with 1D metallic wires have several advantages compared to other forms of material, i.e., powder, 2D sheet, liquid metal. They are easy to handle, radially available, cheap compared to other forms of metals, minimal waste, and homogeneous.

Material Transfer by Dip Coating: Khoda, B. et. al. 2021 JMNM; Khoda, B et. al. 2021 JMSE

Improved understanding of particle transfer processes during dip coating is critical to address current challenges facing the manufacture of next-generation materials and devices, including tubular structures, synthetic blood vessels, tissue scaffolds, flexible electronics, filtrations, and meta-surfaces regulating optical, acoustic, and magnetic waves. The goal of the research is to examine entrapment phenomena that are hypothesized to deliver large inorganic micro-particles (d >1 ┬Ám) to solid substrate surfaces submerged in density-mismatched liquid mixtures, prior to substrate withdrawal. In addition to the significance of this work for the innovative material system, the findings will advance manufacturing processes in transfer printing, foundry coating, material joining, surface protection, and soft robotics. The project will study its underlying physical mechanism in order to understand the interactions between physical governing forces and micro-particle transfer (both entrapment and entrainment).

Resource Efficiency in Additive Technology: Khoda, B. et. al. 2020 JMSE; Khoda, B et. al. 2018 RPJ; Khoda, B et. al. 2017 JMP; Khoda, B et. al. 2017 RCIM

The goal of this research is to create a process behaviors analytics for solid and cellular porous 3D printed objects. One of the major constraints of additive manufacturing processes is that they consume a significant amount of resources (i.e. time, energy and material, support structure and cost) to fabricate parts, which is often tied with the part and process attributes. The objective is to establish a relationship among design, geometry, process variables, material distribution, and AM capabilities while establishing resource consumption mechanism. This research is built upon balancing the hierarchical AM eco-system with primary emphasis on the pre-processing stage followed by the downstream optimization.

Porous infill design and 3D printing: Khoda, B. et. al. 2021 JMSE; Khoda, B. et. al. 2018 RPJ;

A new fabrication pattern for honeycomb infill is proposed for additive manufacturing applications. The proposed pattern will uniformly distribute the material and can accommodate controllable variational honeycomb infill while maintaining continuity with relative ease. The infill structures are fabricated with both uniform and variational patterns which are then compared with the traditional tool-path pattern with compression testing. The results show that the proposed design demonstrates uniform densification under compression and performs better while absorbing more energy. Studying novel pattern and their impact on mechanical properties will help understand the design-performance relationship of the 3D printed parts.

Bio-ink development: Khoda, B. et. al. 2021 JMSE; Khoda, B. et. al. 2019 JMP; Khoda, B. et. al. 2018 Materials;

A hybrid hydro-gel material is designed and developed with alginate, CMC, and nano-cellulose as bio-ink for bio-printing applications. The developed bio-ink material demonstrated higher cell viability (~90%) compare to the common bio-ink (~80%) used in the literature. The bio-ink also demonstrated better mechanical properties and large 3D scaffold structures (>1cm height) were printed with better shape fidelity. The new bio-ink composition will help to design further experiments and study the cell behavior in such a micro-environment. Such investigation will help to answer scientific questions like the cell-material interactions, cell growth dynamics in synthetic media, etc. This will help us to build/manufacture functional tissue and organ in an artificial environment.